中等MATH-FUNC-012
What is the minimum value of y = x^2 − 4x + 7?
A. 7
B. 4
C. −1
D. 3✓ 答案
解說
The axis is x = 2, and y = (x − 2)^2 + 3. The minimum value is 3. The number 7 is the y-intercept, and 2, not 4, is the x-coordinate of the vertex. The question asks for the y-value.